TUT7 Catalyzes the Uridylation of the 3’ End for Rapid Degradation of Histone mRNA

Using high-throughput sequencing of histone mRNAs and degradation intermediates, we find that knockdown of TUT7 reduces both the uridylation at the 3’ end as well as uridylation pattern at the 3’ end, and only had a small effect on the uridylation in the stemloop uridylation of the major during histone mRNA degradation. Knockdown of 3’ hEXO also altered the uridylation of histone mRNAs, revealing a dynamic equilibrium between 3’ hEXO digestion and TUT7 uridylation, suggesting that TUT7 and 3’ hExo function together in trimming and uridylating histone mRNAs. Overall design: We sequenced 3'' ends of histone mRNAs and degradation intermediates before and after inhibition of DNA replication in HeLa cells using the previously described EnD-seq strategy.